Platelet Monoamine Oxidase Activity in Relatives of Alcoholics

To the Editor.—  In the article by Schuckit et al entitled "Platelet Monoamine Oxidase Activity in Relatives of Alcoholics" (Archives 1982;39:137-140), the authors reported finding no statistically significant differences in platelet monoamine oxidase (MAO) activity between male offspring of alcoholics and control subjects matched on a number of relevant variables. Although they noted that there may have been some differences in distribution of platelet MAO levels, the authors concluded that "the present results are not consistent with low platelet MAO activity as a clinically useful marker for the future development of alcoholism" (p 140). However, that conclusion was probably not warranted. The rasults were consistent with the hypothesis, but the lack of statistical power associated with the analysis precluded finding statistically significant effects. Furthermore, comparisons of highrisk and low-risk groups may often be characterized by a lack of statistical power.The authors' findings were as consistent with expectation as one